New feathered dinosaur found

Jeff Poling

Scientists announced in the May 27, 1999, issue of the journal Nature the discovery of another feathered non-avian dinosaur.

The fossil was discovered in Liaoning Province, China, in 1996. This area has also produced the earliest beaked bird known, Confuciusornis, the earliest modern bird known, Liaoningornis, and the three feathered non-avian dinosaurs Sinosauropteryx, a compsognathid, Caudipteryx, an oviraptorid, and Protarchaeopteryx.

The new fossil is of a new type of therizinosaur, an enigmatic group whose placement among the dinosauria has been uncertain and controversial for years. Paleontologists have generally fallen into two camps, placing them as descendants of the prosauropods, an early branch of the sauropod lineage, or among the coelurosaurs, a branch of theropods including advanced meat eaters such as Tyrannosaurus rex, Velociraptor, and birds. The specimen shows certain anatomical characteristics closer to those of oviraptorids than advanced therizinosaurs. This suggests that the feet of therizinosaurs, with their enlarged, non-retroverted first digits, were not inherited from prosauropod ancestors, but were evolved independently from theropod ancestors with feet having reduced, retroverted first digits. The new find, therefore, strongly suggests that therizinosaurs are indeed coelurosaurs.

Also preserved in the fossil are structures very similar to those of Sinosauropteryx. Author Xing Xu writes: "Most integumentary filaments are about 50 mm in length, although the longest is up to 70 mm. Some have indications of branching distal ends." Recent microscopic study of the structures of Sinosauropteryx show they are hollow with branching filaments, and generally indicate that they are a type of feather similar to, but different from, modern bird feathers.

The new dinosaur has been named Beipiaosaurus inexpectus after Beipiao County in which it was found.